The present disclosure is directed to image brightness adjustment of a medical diagnostic system.
Automatic Brightness Stabilization (ABS) technology is a kind of commonly-used brightness adjustment technology in the field of medical X-ray fluoroscopy. In the case that an initial X-ray dose is fixed, different objects (typically patients) may have different X-ray blocking abilities, and X-rays passing through different objects may have different attenuations. If the X-ray attenuation is higher, it may cause the image brightness too dark. If the X-ray attenuation is lower, it may cause the image brightness too bright. Both of these two cases may result in a blurry image. In order to achieve optimum image brightness, the dose of X-rays may be appropriately adjusted. For example, if the image brightness is too dark, the dose of X-rays may be increased; and if the image brightness is too bright, the dose of X-rays may be decreased. The period of adjustment from starting fluoroscopy to make the fluoroscopic image reach the optimum brightness can be called a fluoroscopy ABS time (hereinafter also referred to as “Stabilization time”), which may be one of key performance indicators for measuring X-ray fluoroscopy. During the stabilization time, the X-ray dose received by the object makes no direct contribution to the fluoroscopic image that eventually stabilizes to the optimum brightness, so the shorter the stabilization time the better.
An X-ray tube (hereinafter called “the tube”) is a device for generating X-rays, wherein adjustment of X-ray dose may be implemented by adjustment of fluoroscopic voltage (hereinafter called “fluoroscopic kV”) and fluoroscopic current (hereinafter called “fluoroscopic mA”). The fluoroscopic kV may represent a voltage between an anode and a cathode of the X-ray tube, and usually may be 40-150 kV. The fluoroscopic mA may represent a current between the anode and the cathode of X-ray tube, and usually may be 10-30 mA. During the stabilization time, both the fluoroscopic kV and the fluoroscopic mA may need to be adjusted. The adjustment of fluoroscopic kV may be implemented through the following operations: changing an input signal of an Analog-to-digital converter (ADC) of X-ray high voltage generator (hereinafter called “high voltage generator”), and adjusting the fluoroscopic mA by boosting and rectifying of a high voltage tank. As can be seen, the fluoroscopic kV may be adjusted immediately. The fluoroscopic mA may be implemented by the following operations: setting a filament current provided by a high voltage generator to a tube; and heating filament through the filament current to change the temperature of the filament, which may change the amount of electrons emitted from the filament to the tube anode target surface, thereby changing the fluoroscopic mA. The variation of the filament current causing variation of temperature of the filament may be a relatively slow process, which may take about tens to hundreds of milliseconds and may lead to a longer time for adjusting the fluoroscopic mA once.
A proportion, integration, and differentiation (PID) controller may be adopted for achieving the adjustment of the fluoroscopic kV and the fluoroscopic mA. Specifically, after acquiring a non-adjusted fluoroscopic kV and a non-adjusted fluoroscopic mA and acquiring the image brightness obtained by performing X-ray fluoroscopy on the object based on the fluoroscopic kV and the fluoroscopic mA (hereinafter called “initial brightness), these parameters may be inputted into a PID controller, and the adjustment amount of the fluoroscopic kV and the fluoroscopic mA may be determined based on the difference between the initial brightness and the predetermined brightness, thereby achieving the adjustment of the image brightness. However, since each of the adjustment time for adjusting the fluoroscopic mA might not be short, it may cause the overall stabilization time too long.
NEUSOFT MEDICAL SYSTEMS CO., LTD. (NMS), founded in 1998 with its world headquarters in China, is a leading supplier of medical equipment, medical IT solutions, and healthcare services. NMS supplies medical equipment with a wide portfolio, including CT, Magnetic Resonance Imaging (MRI), digital X-ray machine, ultrasound, Positron Emission Tomography (PET), Linear Accelerator (LINAC), and biochemistry analyser. Currently, NMS' products are exported to over 60 countries and regions around the globe, serving more than 5,000 renowned customers. NMS's latest successful developments, such as 128 Multi-Slice CT Scanner System, Superconducting MRI, LINAC, and PET products, have led China to become a global high-end medical equipment producer. As an integrated supplier with extensive experience in large medical equipment, NMS has been committed to the study of avoiding secondary potential harm caused by excessive X-ray irradiation to the subject during the CT scanning process.